1. Field of the Invention
The present invention relates generally to automotive electronic control modules. More particularly, the present invention relates to an automotive electronic module enclosing electronic circuitry which is sealed hermetically by vibration welding.
2. Disclosure Information
Automotive underhood electronic modules typically contain delicate circuitry such as integrated circuits, power circuit boards and the like used in various operating systems within the vehicle, such as an anti-lock brake system, an engine control system, multiplex system and others. During use, these modules are subjected to extremely harsh conditions such as heat, moisture, and vibration which could have deleterious effects upon the circuitry within the module if the modules are not sealed. Typically, the modules are sealed with a glue such as shown in U.S. Pat. No. 3,909,504 and/or are filled with a resin or potting material, such as shown in U.S. Pat. Nos. 4,546,412 and 4,899,257. Glueing processes are used in sealing the modules to control the amount of vibration imposed on the module to limit damage to the delicate circuitry inside. However, glueing the modules to seal them is a time-consuming manufacturing process. It would be advantageous to provide an alternative manufacturing process for sealing the modules.
Vibration welding, or friction welding, is a manufacturing process by which two work pieces are reciprocated linearly relative to one another under the application of a force, causing the mating surfaces of the work pieces to soften under the influence of friction. After a weld time interval, the work pieces are returned to their original position and they are held in forced contact for a sufficient length of time for the mating surfaces to solidify. Upon solidification, the force ceases and the work pieces are bonded together. Such a technique is shown in U.S. Pat. No. 4,377,428. It has been heretofore unknown to use vibration welding to seal hermetically an electronics control module for a vehicle because of the potential damage which may be inflicted upon the internal circuitry of the module during the relative vibration of the sealing parts.
It is an object of the present invention to seal hermetically automotive electronic modules containing delicate electronic circuitry therein by vibration welding. These and other objects, features and advantages of the present invention will become apparent from the following summary, description, and claims which follow.